cardiopulmonary and analgesics effects of epidural morphine, fentanyl or tramadol in female dog undergoing a ovariohysterectomy

ABSTRACT. Oliveira Neta O.D., Caires L.P., Clark R.M.O, Ferreira M.L., Said R.A., Munhoz A.D. & Tarazi R. [Cardiopulmonary and analgesics effects of epidural morphine, fentanyl or tramadol in female dog undergoing a ovariohysterectomy.] Efeitos cardiorrespiratórios e analgésicos da morfina, fentanil ou tramadol pela via epidural em cadelas submetidas à ovariosalpingohisterectomia. Revista Brasileira de Medicina Veterinária, 36(3):281-288, 2014. Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, Km 16, Salobrinho, Ilhéus, BA 45662-900, Brasil. E-mail: rosanaclark@gmail.com The objective was to evaluate the cardiorespiratory and analgesic effects provided by epidural morphine, tramadol and fentanyl in female dog submitted to ovariohysterectomy. Eighteen healthy female dogs, aged 3.4±2.2 years old, weithing 31.0±8.0Kg, were premedicated with chlorpromazine (0,5mg/kg), with subsequent propofol (5mg/Kg) anesthetic induction by intravenous route and maintenance with isoflurane anesthesia. The animals were distributed in three groups and received: 1,25mg/kg of lignocaine 2% diluted in 0,26ml/kg of saline solution with0,1 mg/kg of morphine (GM group), 5μg/kg of fentanyl (GF group) or 2mg/kg of tramadol (GT group) epidurally.. Heart rate, arterial blood pressure, respiratory rate, end-tidal carbon dioxide (ETCO2 ), oxyhemoglobin saturation (SpO2 ) and body temperature were evaluated before premedication (M0), 15 minutes after premedication (M1), 10 minutes after epidural opioids administration during maintenance and during postoperative period. Postoperative analgesia was evaluated using the by University of Melbourne pain scale (UMPS) and a simple descriptive scale every hour during six hours (M3 – M8). In M2 time, the arterial blood pressure was significantly lower for all treatments and ETCO2 was higher in GM e GT when compared to GF. Pain scores were lower in GM with a UMPS. In the last three times evaluation (M6, M7 e M8), GF group showed significantly higher pain scores compared to other groups. It can be concluded that epidural morphine, fentanyl or tramadol in female dogs undergoing ovariohysterectomy, produced adequate analgesia with minimal side effects, but analgesia was more effective with epidural morphine than other groups. Hypotension and hypercapnia reported during anesthesia may be a result of isoflurane effects.